I want to be able to produce a large amount of gas under water, from a chemical reaction, not from a pressurised cylinder (unless it is just a small cylinder that provides a chemical gas to react with something else to produce the main bulk of gas to inflate the device).

The more gas I can get from the least chemical the better. I know that any gas (even oxygen) can be toxic/dangerous in heavy concentrations, but lets just avoid the "real deadly ones".

A bit of heat from "the reaction" would be acceptable but I can't rely on HOT gases to aid inflation as when they cool and contract I will lose too much volume. It also doesn't want to be too fast/explosive as that could tend to burst the device instead of controlled deployment, even though the device would have a pressure relief valve to prevent over inflation.

So if any chemistry minded people could shine some light on a possible source of gas (30 cubic metres from a brief-case of ingredients) would be good.

2 Responses

Is there a specific application where the typical refillable co2 canisters and air bladders will not do? That solution is about as simple and inexpensive as it could get so I don't see a one use chemical reaction based product doing so well on the market.

As far as chemical reactions go you only have two options. It's either going to fill your bladder quickly and be very hot, or it's going to be cold and take a very long time. Chemical reaction speeds are based closely on temperature, so not only do they need to be hot to react quickly, but you're going to have vastly different reaction times depending on what temperature the water is that they're activated in. Further, assuming you can find a reaction with suitable behavior, you not only need to be sure the gas created is safe, but you need to be sure the chemicals used to create it are environmentally friendly as well in case there is a leak. It just doesn't seem likely to happen.